As the valve opening and closing control apparatus having the configuration as mentioned above, JP 10-227236A (Reference 1) (paragraph number [0054], FIG. 9) discloses a phase changing mechanism that includes a driving side rotating body (a housing in Reference 1) that is rotated synchronously with a crank shaft of an engine of a hybrid type vehicle, and a driven side rotating body (a member having a plurality of vanes in Reference 1) that is rotated integrally with a cam shaft. The phase changing mechanism discloses a configuration that has an advanced angle chamber formed at one side in a rotation direction based on the vane and a delayed angle chamber formed at the other side in the rotation direction, by forming a plurality of protrusion portions protruding to an axis center side inside the driving side rotating body and placing a plurality of vanes in a space formed between the plurality of protrusion portions, and has a control valve which selects one of the advanced angle chamber and the delayed angle chamber and supplies hydraulic fluid.
Reference 1 discloses that the operation of raising the intake compression ratio is carried out, by setting the relative rotation angle between the driving side rotating body and the driven side rotating body to the advanced angle side and reducing the intake compression ratio by setting the relative rotation angle to the delayed angle side, the relative rotation angle between the driving side rotating body and the driven side rotating body is set to the advanced angle side or the delayed angle side by the control of the control valve, and the relative rotation angle is controlled so as to adjust the intake timing of the internal combustion engine.
In the hybrid type vehicle, even if a driver does not perform the operation that stops the internal combustion engine, the control is performed so that when the condition is established, an ECU automatically stops the internal combustion engine, and when the condition is established after the stop, the ECU automatically starts the internal combustion engine. For such reasons, Reference 1 discloses that starting of the internal combustion engine is facilitated after that by changing the relative rotation angle mentioned above to the most delayed angle and locking the angle by a lock mechanism when stopping the internal combustion engine by the ECU.
Without being limited to the hybrid type vehicle, even in an idling stop vehicle that stops the internal combustion engine when the vehicle is temporarily stopped due to waiting for a traffic light or the like, the control of stopping the internal combustion engine and the control of starting the engine are frequently performed. Thus, when starting the internal combustion engine, it is considered that the control of setting the intake compression ratio described in Reference 1 to a low value, reducing load of a compression stroke to facilitate starting, and setting the relative rotation angle between the driving side rotating body and the driven side rotating body to the most delayed angle when stopping the internal combustion engine by the ECU so as to suppress the vibration during starting is effective.
Furthermore, in order to perform starting of the internal combustion engine by setting the relative rotation angle to the most delayed angle, it is also possible to lightly rotate the crank shaft to be connected to starting of the internal combustion engine. However, since the intake compression ratio is low, it is hard to perform suitable combustion, and it is preferable to shift the relative rotation angle to the advanced angle after starting the rotation driving of the crank shaft, in the state of locking the relative rotation angle to the most delayed angle.
However, in a configuration that includes a hydraulic pump driven by the internal combustion engine and performs unlocking of the lock mechanism by hydraulic fluid from the hydraulic pump, the timing of unlocking is delayed due to the oil pressure deficiency, it is difficult to shift the internal combustion engine to the suitable operation state, and so there is room for improvement.
Furthermore, in a configuration that does not use the lock mechanism, maintains the relative rotation angle at the most delayed angle by the oil pressure of hydraulic fluid, and then moves the relative rotation angle in the advanced angle direction, similarly, the rapid movement in the advanced angle direction is delayed due to oil pressure deficiency, it is difficult to shift the internal combustion engine to the suitable operation state, and so there is room for improvement.
An object of this disclosure is to reasonably constitute a valve opening and closing control apparatus that stabilizes the relative rotation angle immediately after starting and then is able to smoothly shift the relative rotation angle in the advanced angle direction.